Triple edge trenching axe

ABSTRACT

A head for a trenching axe has a central eye portion with an eye opening for joining a handle to extend in a first direction and a height in the first direction, a grubbing blade joined to the eye portion, extending away from the eye portion, and having a cutting edge on an end away from the eye portion, the cutting edge facing in a direction substantially orthogonal to the first direction, a first sidewall joined to the grubbing blade along a portion of a first long edge of the grubbing blade, and a second sidewall joined to the grubbing blade along a portion of a second long edge of the blade, the first and second sidewalls each presenting a sharpened edge at substantially a right angle to the cutting edge of the grubbing blade, and a back wall joined to the grubbing blade and the first and second sidewalls, the sidewalls, the grubbing blade and the back wall forming a pocket open toward the cutting edge of the grubbing blade.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to provisional application 60/645,717, filed on Jan. 20, 2005, and incorporates all disclosure of the prior application by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to trenching tools, and more particularly to such tools having an ability for cutting sides of trenches and removing dirt and debris from trenches while forming the trenches.

2. Background

As demand for construction of all sorts increases, so does demand for efficiency in all aspects of the construction processes. The making of trenches is well-known to be a basic process in construction of many sorts, such as in forming foundations for buildings, and in burying utility cables and pipes of all sorts, for example.

There are three general steps in making a trench. Firstly one must break up the soil in the region of the trench. In the process one must cut sides of the trench, and this process often means cutting roots that may pass across the path of the trench. Lastly it is necessary to remove the loosened soil, rocks, cut roots and other debris from the trench.

Trench construction in the conventional art is done quite often by machines, such a “ditch witches” and back hoes. But there is still in the art a need for manual tools for forming trenches, partly because in some cases direct labor is less expensive than the amortized cost of the machines, for example, and in many cases ditches have to be made where machines cannot reach.

Perhaps the best-known tool for manually forming a trench is a pick axe, which is an axe-like tool with a head and a handle. The head is relatively heavy, and has typically a relatively sharp-pointed end for breaking up soil and a wider blade end for cutting, typically across the direction of trench formation. Quite often more than one tool must be used to effectively form a trench; one to break the ground in the right area, such as a conventional pickaxe, using the sharp end and the wide end at different times, another to cut roots crossing the path of the trench, such as a mutt or a conventional axe, and still another, such as a narrow trench shovel, to remove loose material from the forming trench.

An example of a trenching tool in the conventional art is U.S. design Pat. No. D256322 to inventor Zabarte, which includes a head that has a widened pick blade for loosening compacted soil. The widened blade makes it extremely inefficient to use for removing rocks and stones. On the opposite side of the head from the pick blade there is a wide grubbing blade with a sharpened edge and small sidewalls to assist in capturing and removing debris from the forming trench. There is no specification in this document of the intent of the sidewalls, because the document is a design patent, but the apparently sharpened upper edge of the sidewalls shown would not operate effectively to cut sidewalls of a trench in the application of the grubbing blade by swinging the pick axe in the usual manner. Further the short sidewalls would allow for only small amounts of debris to be removed with every pass.

One reason that a variety of tools have to be used when forming a trench is that there is no single tool that performs all of the necessary functions efficiently. What is therefore needed is a new tool that effectively breaks the soil, cuts sides and crossing roots, and removes loose material as well. The new and unique trenching axe described below in various embodiments of the present invention in enabling detail provides all of these functions.

BRIEF SUMMARY OF THE INVENTION

A head for a trenching axe is provided, comprising a central eye portion having an eye opening for joining a handle to extend in a first direction and a height in the first direction, a grubbing blade joined to the eye portion, extending away from the eye portion, and having a cutting edge on an end away from the eye portion, the cutting edge facing in a direction substantially orthogonal to the first direction, a first sidewall joined to the grubbing blade along a portion of a first long edge of the grubbing blade, and a second sidewall joined to the grubbing blade along a portion of a second long edge of the blade, the first and second sidewalls each presenting a sharpened edge at substantially a right angle to the cutting edge of the grubbing blade, and a back wall joined to the grubbing blade and the first and second sidewalls, the sidewalls, the grubbing blade and the back wall forming a pocket open toward the cutting edge of the grubbing blade.

In some embodiments the back wall is a surface of the eye portion, and the sidewalls extend from the grubbing blade to the height of the eye portion. In some other embodiments the back wall is separate from the eye portion. Also in some embodiments the grubbing blade extends from the eye portion further than the extent of the sidewalls from the eye portion.

In some embodiments the back wall is a surface of the eye portion, and the sidewalls extend from the grubbing blade to a height substantially greater than the height of the eye portion. Also in some embodiments each sidewall has a sharpened edge extending from the grubbing blade to the back wall. In many embodiments there is pick end extending from the eye portion similar to that seen on conventional pickaxes.

In another aspect of the invention a trenching axe is provided comprising a head having a central eye portion having an eye opening for joining a handle to extend in a first direction and a height in the first direction, a grubbing blade joined to the eye portion, extending away from the eye portion, and having a cutting edge on an end away from the eye portion, the cutting edge facing in a direction substantially orthogonal to the first direction, a first sidewall joined to the grubbing blade along a portion of a first long edge of the grubbing blade, and a second sidewall joined to the grubbing blade along a portion of a second long edge of the blade, the first and second sidewalls each presenting a sharpened edge at substantially a right angle to the cutting edge of the grubbing blade, and a back wall joined to the grubbing blade and the first and second sidewalls, the sidewalls, the grubbing blade and the back wall forming a pocket open toward the cutting edge of the grubbing blade, and a handle inserted firmly in the eye opening such that the head is joined to the handle at an end of the handle.

In still another aspect a trenching attachment for a pick axe having a grubbing blade is provided, the attachment comprising a first and a second sidewall joined to opposite edges of a mounting plate having the shape and width of the grubbing blade, the first and second sidewalls each having a sharpened edge, a back plate joined to both sidewalls and the mounting plate, and an attachment mechanism for attaching the trenching attachment to a head of a pick axe.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a side elevation view of a triple-edge trenching axe in one embodiment of the present invention.

FIG. 2 is a view of the trenching axe of FIG. 1 in the direction of arrow 2 of FIG. 1.

FIG. 3 is a perspective view of the trenching axe of FIG. 1.

FIG. 4 is a side elevation view of a triple-edge trenching axe in an alternative embodiment of the present invention.

FIG. 5 is a view of the trenching axe of FIG. 4 in the direction of arrow 5 of FIG. 4.

FIG. 6 is a perspective view of the trenching axe of FIG. 4.

FIG. 7 is a side elevation view of a triple-edge trenching axe in another alternative embodiment of the present invention.

FIG. 8 is a side elevation view of a triple-edge trenching axe with a separate pocket and sidewalls in yet another alternative embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a side elevation view of a triple-edge trenching axe 101 in an embodiment of the present invention. FIG. 2 is a view of the axe of FIG. 1 in the direction of arrow 2 of FIG. 1. FIG. 3 is a perspective view of the trenching axe of FIG. 1. In the following descriptions all three of the figures are referenced, using the same element numbers for the various components and features.

Unique trenching Axe 101 has a head portion 116 with a central eye portion 115, common in tools of this sort, which has a tapered opening for joining to a wooden or plastic handle. Head portion 116 has a height H1 in the direction of handle 110, which may typically be 4 to 6 inches, but may vary even more in some embodiments. The handle itself has an enlarged and tapered end matching the size and taper of the eye portion of the head, so the handle can be inserted through the eye from the wider side of the eye, and urging the handle taper into the eye taper joins the handle and the head firmly.

Head 116 in this embodiment has a pick blade 102 equivalent to the pick blade of a conventional pick axe, and a trenching end 103 including a grubbing blade 111 much like the grubbing blade of a conventional pick axe. In the embodiment of the invention illustrated in the three figures, however, there are additionally unique sidewalls 104 and 105 joined to grubbing blade 111 in a manner to create a pocket 112 (see FIG. 3), and to provide two sharpened blade edges 107 and 108 on a leading edge of each sidewall, leading edge meaning for this specification in the direction of travel when swinging the tool in the conventional manner. Sidewalls 104 and 105 may be joined to grubbing blade 111 in any manner known in the art, such as welding, or the grubbing blade and sidewalls may be formed by such as a casting or a swaging operation. It will be apparent to the skilled artisan that there are a number of ways the unique structure may be formed.

Edge 109 of grubbing blade 111 is a sharpened edge as is common for grubbing blades, and is presented as a leading edge in the direction a user would swing the trenching axe in use. Edges 107 and 108 of sidewalls 104 and 105 are also sharpened edges, and present as leading edges in the direction of application as well, but at substantially ninety degrees from the line of edge 109.

In this particular embodiment the geometry of trenching end 103 of head 116 is such that edge 109 is spaced away from the handle further than edges 107 and 108, with the sidewalls extending less than the full length of grubbing blade 111. The distance of extension of edge 109 beyond that of edges 107 and 108 may vary according to a number of factors, but in some embodiments is about three inches. This is not an essential limitation in the invention, and in some cases the sidewalls may extend the full length of the grubbing blade or for an extent less than that shown in the figures.

In a trenching operation a user will swing the triple edged trenching axe of the invention in the same manner as one would swing a conventional pickaxe, assuming using the grubbing blade. In the embodiment described with the aid of FIGS. 1-3 edge 109 of grubbing blade 111 will impact the soil before edges 107 and 108 because of the extension difference described above. As the grubbing edge 109 penetrates the soil, sharp edges 107 and 108 will also penetrate the soil defining sides of a developing trench. Edges 107 and 108 cut shape trench sides, and cut any intervening roots or other material. Moreover sides 104 and 105 form a pocket 112 with grubbing blade 11, which facilitates removal of soil or other material from the developing trench.

In the embodiment described with aid of FIGS. 1-3 sidewalls 104 and 105 have a height in the direction of the handle substantially the same as height H1 of head 116, which is also the height of central eye portion 115. In the embodiment described above the sidewalls extend to eye portion 115 and are preferably joined to the eye portion by such as welding to form a complete pocket 112. FIG. 2 is a view of trenching axe 101 in the direction of arrow 2 of FIG. 1, looking at a small upward angle into pocket 112. The integrity of the pocket thus formed is considered by the inventors to be important to the object of removing material from the developing trench when the trenching axe is withdrawn after a digging stroke.

In alternative embodiments a variety of changes may be made to the geometry of the trenching axe of FIGS. 1-3. FIGS. 4-6 illustrate one such alternative. FIG. 4 is a side elevation view of a triple-edge trenching axe 401 in an alternative embodiment of the present invention. FIG. 5 is a view of trenching axe 401 in the direction of arrow 5 of FIG. 4. FIG. 6 is a perspective view of trenching axe 401.

In the embodiment of FIG. 4-6 trenching axe 401 has sidewalls 404 and 405 joined to a grubbing blade 411 that extend in the direction of the handle to a considerably greater height than the sidewalls of the trenching axe described with aid of FIG. 1-3. This feature is useful in the case of looser and lighter soil, allowing a pocket 412 of greater volume to trap a greater quantity of material to be dislodged and moved out of the developing trench with each stroke of the trenching axe. Sidewalls 404 and 405 are joined to central eye portion 415 as before, and extend proximate handle 410. It is not necessary that the sidewalls be joined to the handle, only that they are close to the handle to avoid loss of loose material in use.

Grubbing blade 411 still has a sharpened edge 409 extending in the direction of action, and in this embodiment sidewalls 404 and 405 have sharpened edges 407 and 408 respectively also presenting substantially in the direction of action. In some embodiments the sharpened edges of the sidewalls may extend further than the extent shown in FIGS. 4-6, and in some cases for the full extent of the sidewalls back to the handle.

FIG. 7 is a side elevation view of a triple-edge trenching axe in another alternative embodiment of the present invention. In the trenching axe of FIG. 7 sidewalls 704 and 705 have a different curved shape from grubbing blade 711 to handle 710 and sharpened edges 707 and 708 extend for the full extent of the sidewalls from the grubbing blade to the handle. This feature is useful under certain conditions where a great quantity of roots or other obstructions may be expected where a trench is to be formed.

Also in the embodiment illustrated in FIG. 7 a separate back wall 714 is provided joined to the sidewalls to complete the pocket. In some cases a bracket 712 is added to attach the sidewalls to the handle to provide additional strength, although this feature is not needed in every case.

Yet another innovation is shown in FIG. 8, in which illustrates a conventional pick axe 801 to which a separate pocket and sidewall unit 802 may be assembled to provide a triple-edge trenching axe according to an embodiment of the invention. Unit 802 has sidewalls 804 and 805, of which 804 may be seen, a back wall 812, and a top wall 814 of a width to match grubbing blade 803 of the conventional pick axe. Sidewalls 804 and 805 are welded to the top wall and the back wall in this embodiment in a manner that unit 802 may be assembled over blade 803 and may be secured to handle 810 by a bracket 812. In some cases set screws or other aids my be used to help secure unit 802 to a conventional pick axe, and when unit 802 is in position, the conventional axe becomes a triple-edge trenching axe according to an embodiment of the present invention.

It will be apparent to the skilled artisan that the trenching axes illustrated and described in different embodiments herein, and separate units to add to conventional axes, may have different features in different versions for a number of reasons. For example, there may be axes or axe heads of different weight and size, for different users and different purposes. Further, the components may be made of different materials, primarily metal for the head, in different embodiments. The width of the grubbing blade and its magnitude of extension beyond axe blades 107 and 108 may also vary. In some embodiments there is no pick end, and the trenching axe is solely for forming trenches with the triple-edge end. There are many other variations that will fall within the spirit and scope of the invention. The breadth of the invention is therefore limited only by the claims that follow. 

1. A head for a trenching axe, comprising: a central eye portion having an eye opening for joining a handle to extend in a first direction and a height in the first direction; a grubbing blade joined to the eye portion, extending away from the eye portion, and having a cutting edge on an end away from the eye portion, the cutting edge facing in a direction substantially orthogonal to the first direction; a first sidewall joined to the grubbing blade along a portion of a first long edge of the grubbing blade, and a second sidewall joined to the grubbing blade along a portion of a second long edge of the blade, the first and second sidewalls each presenting a sharpened edge at substantially a right angle to the cutting edge of the grubbing blade; and a back wall joined to the grubbing blade and the first and second sidewalls, the sidewalls, the grubbing blade and the back wall forming a pocket open toward the cutting edge of the grubbing blade.
 2. The trenching axe head of claim 1 wherein the back wall is a surface of the eye portion, and the sidewalls extend from the grubbing blade to the height of the eye portion.
 3. The trenching axe head of claim 1 wherein the back wall is separate from the eye portion.
 4. The trenching axe head of claim 1 wherein the grubbing blade extends from the eye portion further than the extent of the sidewalls from the eye portion.
 5. The trenching axe head of claim 1 wherein the back wall is a surface of the eye portion, and the sidewalls extend from the grubbing blade to a height substantially greater than the height of the eye portion.
 6. The trenching axe head of claim 1 wherein each sidewall has a sharpened edge extending from the grubbing blade to the back wall.
 7. The trenching axe head of claim 1 further comprising a pick end extending from the eye portion in a direction opposite the extension direction of the grubbing blade.
 8. A trenching axe comprising: a head having a central eye portion having an eye opening for joining a handle to extend in a first direction and a height in the first direction, a grubbing blade joined to the eye portion, extending away from the eye portion, and having a cutting edge on an end away from the eye portion, the cutting edge facing in a direction substantially orthogonal to the first direction, a first sidewall joined to the grubbing blade along a portion of a first long edge of the grubbing blade, and a second sidewall joined to the grubbing blade along a portion of a second long edge of the blade, the first and second sidewalls each presenting a sharpened edge at substantially a right angle to the cutting edge of the grubbing blade, and a back wall joined to the grubbing blade and the first and second sidewalls, the sidewalls, the grubbing blade and the back wall forming a pocket open toward the cutting edge of the grubbing blade; and a handle inserted firmly in the eye opening such that the head is joined to the handle at an end of the handle.
 9. A trenching attachment for a pick axe having a grubbing blade, the attachment comprising; a first and a second sidewall joined to opposite edges of a mounting plate having the shape and width of the grubbing blade, the first and second sidewalls each having a sharpened edge; a back plate joined to both sidewalls and the mounting plate; and an attachment mechanism for attaching the trenching attachment to a head of a pick axe. 